The Democratic nominee’s early exit from the memorial service in New York is likely to be used by Republicans to raise more questions about her fitness for the White House.

US Democratic presidential candidate Hillary Clinton leaves the ceremony, marking the 15th anniversary of the September 11 attacks in New York.(Reuters Photo)

Democratic presidential candidate Hillary Clinton on Sunday left a ceremony to mark the 15th anniversary of the 9/11 attacks early after feeling unwell.

Clinton’s early exit from the memorial service in New York because she felt “overheated” is likely to be used by Republicans to raise more questions about her health.

A Clinton campaign spokesperson said in a statement the nominee “felt overheated so departed to go to her daughter’s apartment, and is feeling much better”. Clinton later told reporters she was “feeling great”.

Both Clinton and Donald Trump were at the event held every year at Ground Zero, where the twin towers of the World Trade Center stood before being struck on September 11, 2001.

Clinton left the event 30 minutes before it was scheduled to end, setting off speculation of a “medical event”, noted and repeated on social media eagerly by Republicans and conservatives. They have already tried to raise questions about her health using rightwing conspiracy theories, without any evidence, to argue she is not healthy for running the White House.